.main {
  overflow: hidden;
  bottom: 132px;
  width: 100%;
  height: 750px;
  background: url(../upload/home_wrap20181203.jpg);
}
.main .logo_mxd {
  margin-right: 100px;
  margin-top: 50px;
}
.main .nav {
  position: relative;
  width: 704px;
  height: 385px;
  background: url(../img/index_main.png);
  margin: 200px auto;
}
.main .nav > a {
  display: inline-block;
  width: 132px;
  height: 40px;
  margin-top: 24px;
  margin-left: 22px;
}
.main .link {
  position: absolute;
  bottom: 0;
  width: 700px;
  height: 300px;
  background: url(../upload/14943128782426.png);
}
.main #link_main {
  width: 100%;
  height: 100%;
  display: block;
}
.main .circle {
  background: url(../img/download_bg.png) no-repeat;
  position: absolute;
  left: 50%;
  margin-left: 110px;
  top: -60px;
  width: 100%;
  height: 100%;
}
.main .circle .mxd_download {
  display: block;
  background: url(../img/home_btn.png) no-repeat 0px 0px;
  width: 200px;
  height: 200px;
}
